Power transmission device



Feb. 1, 1938.

J. J. HO'EHN ANSMISSION Filed Feb. 27, 1932 m my J. w n m J Patented Feb. 1 1938 PATENT OFFICE POWER TRANSMISSION DEVICE John J. Hoehn, Camden, N. J., assignor to Radio Corporation of America, a corporation of Dela ware.

Application February 27, 1932, Serial No. 595,458

3 Claims. 01.; 2714-9) My invention relates to power transmission devices and, more particularly, todevices of this character which are advantageously applicable to phonograph turntables and the like.

Specifically, my invention is in the nature of an improvement over the devices disclosed in the co-pending application of Frederick C. Barton, Serial No. 592,704, filed February 13, 1932, and the co-pending application of Thaddeus R. Goldsborough, Serial No. 589,968, filed January -30, 1932, both of said applications being assigned to Radio Corporation of America. Both of the aforementioned applications disclose the use of planetary gearing of the ball type for the pur-' pose oi driving a phonograph turntable at a speed lower than that of the customary turntable Supporting spindle. In neither application, however, is there disclosed commercially practicable means for shifting from one turntable speed to another.

It is, accordingly, an object of my invention to provide inexpensive means whereby slowspeed, long-playing records and standard highspeed records may be reproduced on existing phonographs designed originally for reproducing only'standard high-speed records.

A further object of my invention is to provide a simple, inexpensive attachment for existing phonographs whereby either standard or the new long-playing records may be reproduced at the will of the operator.

Another object of my invention is to provide, in a standard phonograph, a record support or turntable which is interchangeable with the conventional turntable whereby both standard highspeed and. the new long-playing records may be 1 selectively reproduced thereon at will.

I A further object' of my invention is to provide, in a standard phonograph, a turntable which is interchangeable with the conventional turntable thereof whereby the turntable speed of standard phonographs may be selectively changed from one to another predetermined speed without in any way altering the turntable spindle, the normal driving speed of the driving unit thereof, or the motorboard of such phonographs.

Another object of my invention is to provide a record support which is interchangeable with standard record supports or turntables and which has a manually controlled automatic speed changing mechanism permanently attached thereto whereby, when said turntable is substituted for a standard record support operable at one predetermined constant speed, the same or another predetermined constant speed is selectively available at will. 7

A further object of my invention is to provide a turntable which is interchangeable with the turntable normally forming a part of a standard phonograph whereby the normal reproducing speed of the phonograph may be selectively changed to another predetermined reproducing speed without removing the interchangeable turntable, changing the speed of the phonograph motor or the turntable supporting spindle driven by the motor.

Another object of my invention is to provide a turntable which is interchangeable with the turntable of a standard type of disc phonograph whereby, when the interchangeable turntable is mounted on the supporting spindle and the phonograph placed in operation, the new turntable may be rotated at either the same speed as that of the spindle or at a speed different than that of. the spindle, at the option of the operator.

A further object of my invention is to transform standard phonographs having but a single turntable operating speed into plural speed phonographs whereby the reproducing speed of the turntable may be. selectively changed from one to another reproducing speed after a turntable constructed in accordance with my invention has been substituted in place of the conventional phonograph turntable.

Another object of my invention is to provide a record support which is interchangeable with Another object of my invention is to provide an impro ed turntable assembly whereby, whenthe turntable is placed upon the spindle of a standard high-speed phonograph, the speed of theturntable may be quickly and easily changed from any one of a plurality of speeds to another desired speed, and vice versa.

And still a further object of my invention is/ to provide an improved turntable unit for the proper reproduction of both high-speed and slow-speed records on a single phonograph, the unit being simple in construction, efficient in use and readily lending itself tc economical manufacture.

Other objects of my invention will become evident from the following detailed description taken in conjunction with the accompanying drawing, in which Figure 1 is a sectional assembly view of. a plural speed turntable carrying an improved selective speed changing mechanism in accordance with my invention and mounted on the turntable supporting spindle of a disc phonograph of coriventional type, the parts being shown in position for operating the turntable relative to the spindle, i. e., at a speed difierent than the speed of the spindle.

Fig. 2 is a fragmentary exploded view, inperspective, of the control means for 'the speed rows 5-5.

Referring more particularly to the drawing, wherein similar reference characters indicate corresponding parts throughout, a motor-board I0 having a central clearance opening ll therein and a turntable supporting spindle l2 carrying a driving pin l3 and extending vertlcallythrough the opening I l form parts of a conventional type of disc phonograph and are shown to illustrate the application of my invention thereto. The spindle I2 may be driven from a motor l2 of any desired type.

In accordance with my invention, arecord supporting platen l4, forming a turntable of conventional design, is provided with a centrally depending hub or boss l5 having a central bore l6 which extends through the hub l 5 for the free passage therethrough of the spindle l2, as clearly shown in Fig. 1.

Formed concentrically with the hub l5 adjacent the underside of the turntable I4 is a shoulder IS on which an annularball cage or driving member I! is suitably staked, welded or otherwise secured, with the annular wall l8 of the said member I! depending from the shoulder l6 in spaced relation to the periphery of the hub I 5. Formed in the annular wall l8 of the member I! are a plurality of equally spaced, vertically arranged slots l9 which extend inwardly from the lowermost peripheral edge of the wall I 8 to a point substantially intermediate the length of the driving member l1.

Rotatably mounted on the lower end portion of the turntable hub i5 is a counter-bored sleeve having a relatively smaller bore 2| in the lowermost end thereof in axial alignment with the larger uppermost bore 22, the bore 2| being of the same size as the bore l6 so that the bores l6 and 22 will register for the sliding passage there- ,through of the spindle l2. A shoulder 23, formed in the sleeve 20 by the diifering diameters of the axially aligned bores i6 and 22, is provided with a suitable washer 24 upon which the bottom face of the hub l5 seats.

Longitudinal movement of the counter-bored sleeve 20 on the hub I5 is prevented after placement thereon by means of an offset locking pin 25 which so extends transversely through the sleeve 20 that the intermediate portion of the pin 25 will register with an annular groove 26 formed in the periphery of the hub l5 adjacent its lower free end, asclearly shown in Fig. 1. The counter-bored sleeve 20 is further provided with a transverse slot 21 which is cut centrally across the bottom face thereof and is adapted to receive the driving pin l3 carried by the spindle l2, whereby the sleeve 20 is rotated in response to the spindle l2 and is supported against further downward movement thereon in a manner well known to those skilled in the art.

Secured to the upper end portion of the counter-bored sleeve 20, as by means of a press fit thereon, is a bearing assembly 28 comprising an inner raceway 29, an outer raceway 36, and a plurality of balls or rollers 3| disposed between said raceways. The inner diameter of the raceway 29 and the outer diameter of the sleeve 20 are such that the bearing assembly generally indicated at 28, may be pressed thereon to the depth of the shoulder 32 on the sleeve 20 to insure the rotation of the inner raceway 29 with the sleeve 20. The annular driving member I 1 depends in the space between the inner and outer raceways 29 and 30, respectively, which space is maintained by the balls or rollers 3|. The spaced, vertical slots l9 formed in the annular wall of the driving member I! are of a size suflicient to receive the balls 3| therein to maintain the said balls in equally spaced relation and to transmit motion from the sleeve 20 to the driving member I! and the turntable l4.

In order that theturntable ll may be rotated I relatively to the spindle l2, or at a speed different than the speed of the spindle, the outer raceway of the bearing assembly 28 must be restrained against rotation. To this end, a split collar 33 is suitably clamped about the periphery of the outer raceway 30 by means of a bolt 34. A clevis bracket 35 is spot welded or otherwise attached to the periphery of the collar 33 at a point substantially diametrically opposite to its split ends for the pivotal reception of a U-shape hinge bracket 36 by means of a pivot pin 31.

A resilient restraining member 38 is attached to the hinge bracket 36, as by means of a rivet 39 or the like, with its inner end 40 bent sub stantially upwardly so as to engage the rear wall ll of the clevis bracket 35, wherebya spring action is obtained for urging and normally retaining the other end of the member 38, to be presently described, in engagement with the motor-board l0. Clockwise pivotal movement of the bracket 36 (as viewed in Fig. 1) is limited,,

however, by a stop plate 42 which is formed on the clevis bracket 35 and projects laterally therefrom for engagement with the bottom side of the hinge bracket 36, as clearly shown in Fig. 1.

The resilient member 38 has its outer free end 43 bent downwardly and is also suitably notched as at 44 to provide a plurality of serrations or teeth 45 which are adapted to slightly dig into the surface of the motor-board I 0, whereby the outer raceway 30 is securely held against rotation.

If it is desired that the turntable H be rotated at the same speed as that of the spindle I 2, the outer raceway 30 is preferably, although not necessarily, locked to the turntable H. To this end, a suitable elongated slot 46 is formed in the turntable I4 radially of its axial center whereby a manuallyoperable control member, hereinafter described, may be actuated.

A slide bar 41 having an upstanding pin 48 secured thereto intermediate its ends is attached to the underside of the turntable M in sliding relation thereto by means. of a pair of oflset brackets 49 which may be spot Welded or otherwise attached to the turntable M. The pin 48 extends into the slot 46 so that the slide bar 41 may be moved in a radial path toward and away from the spindle l2.

A latch element generally indicated at 50 is formed on one end of the slide bar 41 at right angles thereto and comprises an inclined edge 5| 7o which is provided with a step or recess 52 adjacent the slide bar 41. As clearly shown in Fig.

. 2, a laterally projecting arm 53 is formed on one of the upstanding side members of the U-shape bracket 36 for co-operative engagement with the latch element 56 when the slide bar 4'! occupies a position nearestto the spindle l2 to position the inclined edge 5| of the latch member 56 in the path of the aforesaid arm 53. When the slide bar 41 is 50 positioned and the turntable I4 is rotated, the latch element 50 carried thereby will ride under the arm 53 and rotate the bracket 36 about its pivot 31 sufliciently to raise the resilient restraining member 33 out of engagement with the surface of the motor-board l0, whereby the outer raceway 30 is simultaneously locked to the turntable I4 for rotation therewith.

A simplified modification of the clevis bracket 35, U-shape bracket 36 and the resilient restraining member 38 carried thereby, is illustrated in Figs. 4 and 5 wherein a U-shape bracket 54 corresponding to the clevis bracket 35 is attached to the split collar 33. The laterally projecting spaced members 55 of the bracket 54 are, however, each providedwith'rectangular, vertically aligned slots for the slidable reception therein of an L-shape restraining member 56 which takes the place of the bracket 36 and the resilient member 38 shown in Figs. 1, 2 and 3.

lowermost end portion suitably notched or cut out to provide a plurality of teeth or pointed ends 51 which are normally held in firm engagement with the surface of the motor-board III by means of a spring 56 having its lowermost end anchored to the bracket 54 and its other end to a laterally extending arm 59 on the L-shape member 56. The arm 59 is also adapted to ride up on an inclined tongue 66 formed on the inner end of a slide bar 6|, similar to the previously described slide bar 41, for elevating the L-shape member 56 against the action of the spring 53 to free its pointed ends or teeth 51 from engagement with the motor-board l6.

I Operation In considering the operation of my invention it is to be noted that the spindle l2 and the inner raceway 29 constitute a driving member; the

. turntable or record supporting platen I4 is, of

course, the .driven member; while motionis transmitted from the driving member to the driven member or turntable by the co-operation of the outer. raceway 36, the balls 31 and the sleeve or ball cage l8, which latter three are associated with the turntable l4 in the manner heretofore described and constitute the motion or power transmitting mechanism.

Assuming, now, that the turntable shown in Fig. 1 with the slide bar 41 in the position shown in full lines is being rotated and the outer raceway 36 restrained against rotation by the engagement of the resilient arm 36 with the motorboard It, the turntable l4 will rotate relatively reason of the rotation. of the inner raceway. In so rolling, the balls carry the depending cage with them at a speed lower than that of the spindle with the result that the turntable is also caused to rotate at the same reduced speed.

Assume, now, that it is desired that the turntable l4 rotate at the same speed as that of the spindle l2. The finger piece or pin 48 is then moved to the inner end of the slot 46 to position the slide bar 41 in the position indicated by the broken lines in Fig. 1. This movement places the latch element 56 in the path of the laterally projecting arm 53 carried by the bracket 36. As soon as the latch element 56 engages with and rides under the arm 53 upon rotation of the that when the spindle I2 is being rotated at a predetermined, constant speed, either one of two turntable speeds is available for reproducing either the well known standard records operable substantially'at an angular speed of 78 R. P. M., or the new long playing records operable at an angular speed of 33% R. P. M., by the selective shifting of the slide bar 41 by means of the finger piece or pin 48, which projects into the The L-shape restraining member 56 has its slot 46 a distance suflicient for manually grasping the pin 43 but not to such an extent as'to interfere with the proper positioning of a record disc on the turntable l4. I

Although I have shown and described certain embodiments of my invention, I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim as my invention:

1. In a phonograph, the combination of a driving spindle, a turntable, means including speed changing mechanism attached to said turntable and mounted on said spindle for transmitting power from said spindle to said turntable, means constantly tending to condition said mechanism to drive said turntable at a speed other than that of said spindle; and means for rendering said last-named means ineffective to so condition said mechanism whereby said mechanism is conditioned to drive said turntable at the same speed as said spindle.

2. In combination, a driving device a driven device, power transmission mechanism connecting said devices and comprising inner and outer relatively moveable members, a laterally extending arm pivotally mounted on said outer 'memher, and means carried by said driven device adapted to engage said arm for controlling the relative movement of said members.

3. In combination, a driving device, a driven device, power transmission mechanism connecting said devices and comprising inner and outer relatively moveable members, a laterally extending arm pivotally mounted on said outer membet, and means carried by said driven device adapted to engage said am for locking said members together to rotate as a unit.

JOHN J. HOEHN. 

